While there have been rumors and speculation about a potential MMO in the past, no official information has been released.
It's important to note that:
* The last Star Trek MMO, Star Trek Online, is still being updated and supported. This means there isn't a need for a completely new MMO right now.
* There are many other Star Trek games in development, including Star Trek: Resurgence and Star Trek: Prodigy.
It's possible that a new Star Trek MMO could be announced in the future, but for now, there's no concrete information about a release date.